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Re: Method for a client to determine if what it PUT/POSTed will be the same as what it would GET



On Jan 29, 2008 10:49 PM, Brian Smith <brian@xxxxxxxxxxxxxx> wrote:
> Even if the server is trying to keep them in sync, you cause problems when the entry is being cached in such a way that the MD5 hash and ETag are stale. You have to do a HEAD on the media resource to (attempt to) verify that the media link entry is up-to-date.  If you have to do a HEAD request and you are depending on the server to calculate an MD5 hash anyway, then why not just depend on the server to send a Content-MD5 in response to the HEAD request?

Agree. :-) Given that an AtomPub client will be programmed to send out
Content-MD5 header when PUT/POST a media resource, then sending a
subsequent HEAD by assuming server will return a Content-MD5 header in
response. The assumption is implicitly made by client. Will it be
worth to make this assumption explicit, probably announced by server,
e.g. label a media collection with specific f:feature?

-- 
Teo Hui Ming